Tracing the three-dimensional pathways of water parcels and particles in the upper ocean is of importance from many perspectives. Observation, understanding and prediction of the three-dimensional pathways by which water from the surface ocean makes its way into the deeper ocean is the goal of this research.
During May of 2018 a pilot cruise in the framework of the CALYPSO ONR Departmental Research Initiative took place on the Alboran Sea in the Western Mediterranean Sea. This region is characterized by a strong semi-permanent front between the fresher Atlantic water that enters the Western Mediterranean at Gibraltar, and the more saline Mediterranean waters. It is populated by organized, time evolving features (jets, fronts, and gyres) that provide an ideal test bed for a dynamical systems-based Lagrangian analysis. During this cruise nearly a hundred drifters were deployed (between SVP, CODE and CARTHE drifters).
In this work we use a least square method to calculate the differential kinematic properties of flow, divergence, vorticity and lateral strain from a set of drifters. These values are obtained through the study of the evolution in time of a patch formed by a cluster of drifters. Results from drifters at different depths, surface and 15m, show different dynamics in these layers. To estimate the validity of the results, an numerical analysis is performed by advecting particles on a numerical model where the kinematic properties are known.